This invention relates generally to gas turbine engines, and more specifically to seal assemblies used with gas turbine engine rotor assemblies.
At least some known gas turbine engines include a core engine having, in serial flow arrangement, a fan assembly and a high pressure compressor which compress airflow entering the engine, a combustor ignites a fuel-air mixture which is then channeled towards low and high pressure turbines which each include a plurality of rotor blades that extract rotational energy from airflow exiting the combustor. The high pressure compressor is coupled by a shaft to the high pressure turbine.
To facilitate sealing between rotor shafts, at least some known turbines include a plurality of seal assemblies to facilitate containing fluid within predetermined locations. For example, at least some known engines include a bearing compartment that is filled with an oil mist to provide lubrication to bearings that support an inner and outer rotor shaft. The inner and outer shafts are separated by a gap that may be filled with a working fluid used to cool the shafts. A seal assembly is used to prevent the oil mist from leaking into the gap defined between the shafts.
At least some known seal assemblies include a first portion that is coupled to the first rotor shaft and a second portion that is coupled to the second rotor shaft. However, because both seal assembly portions are rotating independently, such seal assemblies may be susceptible to leaking when thermal, mechanical, and centrifugal forces are induced to either or both rotor shafts. Other known seal assemblies include a first seal portion that is mounted to a stationary structure between the rotor shafts, such as an engine frame, and a second portion that is mounted to one of the rotor shafts. Because of the limited space between shafts, such seal assemblies are typically only used near an end of a shaft, and as such, may  also be susceptible to deflections and/or rotor excursions cased by thermal, centrifugal, and/or gyroscopic forces induced to the rotor shaft.